It is proposed to characterize the properties of solid-phase bound specific cDNA as an affinity column to determine its suitability for the isolation of the hnRNA for an immunoglobulin L-chain (MOPC 21). Should this procedure prove successful, the column will be used to purify labeled L-chain hnRNA from mouse myeloma cells pulsed for short periods with 32P-phosphate. Biochemical analyses will be performed on isolated material to determine its purity, heterogeneity and molecular weight. Fingerprint analysis using T-RNase will be undertaken to ascertain whether oligonucleotides known to code for sections within the V- and C-regions of the MOPC 21 L-chain are present (integrated) in a single molecular species. Experiments will also be performed to improve on methods for obtaining 5'-32P-labeled mRNA in undegraded form suitable for sequence analysis using base-specific enzymes (T1 RNase, pancreatic RNase, U2 RNase etc.). These experiments will be aimed at devising purification procedures that yield decapping enzyme and polynucleotide kinase that are free from unwanted endo- and exoribonuclease activity.